Search on : Taxa descriptions


 Add this item to the list  819996 Original description
Remarks (public):Phlyctis tolgensis is characterized by the thin and thinly corticate, greenish white thallus containing protocetraric and physodalic acids, moderately large, immersed to emergent apothecia with a greenish white-pruinose, dark greyish brown disc, a thick, dark brown proper excipulum, monosporous asci and amyloid, muriform ascospores 87–152 × 25–55 µm. The corticolous, southern Indian species P. subagelaea is most similar, having monosporous asci and amyloid, muriform ascospores (Joshi et al. 2010). However, the latter has narrower ascospores (12–30 µm wide) and an ecorticate thallus said to contain fumarprotocetraric acid. However, the spot test reactions cited for P. subagelaea, K+ yellow, KC+ red, PD+ orange (Joshi et al. 2010), suggest that additional or alternative compounds are most likely present (Elix 2014). Efforts to obtain the type specimen of P. subagelaea from LWG on loan were not successful. Three other species of Phlyctis have an esorediate thallus, monosporous asci and muriform ascospores. Phlyctis nepalensis Räsänen has a K– thallus containing an unidentified compound as well as comparatively small ascospores (45–53 × 12–16 µm; Joshi et al. 2012). Both the North American P. speirea G.Merr. and P. chilensis D.J.Galloway & Guzmán, from southern Chile, contain norstictic acid (K+ red), the former having apothecia to 0.6(–0.8) mm wide (Tønsberg 2004), while the latter has an arachnoid-byssoid thallus and considerably larger ascospores (190–285 × 55–70 µm; Galloway & Guzmán 1988). The new species is known from bark in the canopy of a rainforest remnant at the type locality, near Tolga on the Atherton Tableland, north-eastern Queensland, Australia. 
Description type:Original description 
Description:Thallus corticolous, crustose, epiphloeodal, forming a colony 5.5 cm wide, 40–80 µm thick, greenish white, smooth to minutely and irregularly uneven, dull but somewhat glossy towards the margin, continuous to richly but faintly rimose, not areolate, lacking calcium oxalate (H2SO4–), I–. Cortex 6–9 µm thick, hyaline, of long-celled, periclinal, prosoplectenchymatous hyphae 1–2 µm wide. Algae occupying most of the thallus; cells chlorococcoid, ± globose, 6–10(–12) µm wide; interstitial hyphae short-celled, 1.5–2.5 µm wide. Medulla indistinct. Prothallus silvery white, diffuse and fimbriate when overgrowing bare bark, to 2.5 mm wide. Apothecia moderately numerous, mostly scattered, immersed in thalline verrucae to emergent, rounded, oblong or irregular in outline, (0.45–)0.84(–1.4) mm in maximum extent [n = 50]; disc plane to slightly convex, concolorous with the thallus due to its thick pruina, this dissolving in K (or sometimes eroding) to reveal the dark greyish brown surface; thalline margin rather prominent, 80–150(–200) µm thick, entire to irregularly broken or crenulate, anatomically identical with the thallus. Proper excipulum cupulate, dark brown, 20–30 µm thick laterally, 25–50 µm thick above the apothecial base, paraplectenchymatous, with minute, thick-walled cells. Hypothecium hyaline, 25–40(–50) µm thick, non-amyloid. Hymenium 100–160(–190) µm thick, not inspersed with granules or oil globules. Epihymenium dominated by a layer of pruina 25–50 µm thick which dissolves in K, subtended by a medium brown-pigmented zone 20–30 µm thick. Paraphyses strongly conglutinate in water, embedded in hymenial gel, loosening in K, mostly simple below, or with sparse to abundant distal branches (with rare anastomoses), long-celled, 1–1.5 µm thick; apical cells not or scarcely swollen, hyaline, to 2 µm thick. Asci narrowly to broadly clavate, 1-spored, 95–160 × 28–50(–60 µm) [n = 20], with a short, gradually tapering stalk; apex broadly rounded, without a distinct apical apparatus, 4–8 µm thick; wall non-amyloid; ascoplasma of immature asci IKI+ pale to medium reddish; most submature and mature ascospores IKI+ dark blue to blue-black, a minority remaining IKI+ reddish. Ascospores colourless, narrowly ellipsoid to oblong-ellipsoid, muriform, with 23–30(–33) transverse divisions, each transverse locule with 5–7(–8) longitudinal divisions, lacking a perispore, with rounded ends, frequently a little broader towards the proximal end and tapering distally, (82–)115(–152) × (25–)35(–55) µm [n = 40]; spore wall c. 2–3 µm thick; cells mostly cuboid, their contents clear. Pycnidia not seen. Chemistry: Thallus K+ pale brown, C–, KC–, PD+ orange-red, UV–; protocetraric acid (major), physodalic acid (minor) by TLC. 
Taxon name: